A three-speed intelligent pid control method

Abstract

The invention relates to a three-speed intelligence PID control method independent on a controlled object model and aims at the difficulty of setting of traditional PID controller gain, wherein the system dynamics and internal and external uncertainties are defined as summation disturbance; thereby, a nonlinear uncertainty system is transformed into a linear uncertainty system; further, an error dynamic system under excitation of the summation disturbance is constructed; accordingly, a three-speed intelligence PID controller mode with a central speed factor as the core is designed. Through theoretical analysis, not only a closed-loop control system composed of the three-speed intelligence PID controller has overall asymptotic stability robustness, but also the three-speed intelligence PIDcontroller has excellent disturbance rejection robustness. The three-speed intelligence PID control method in the invention lays a good technical foundation for technical upgrading of various types ofPID controllers in the existing operation and has wide application value in the fields of electric power, mechanical engineering, chemical engineering, light engineering, transportation, aviation, aerospace and the like.

Description

technical field [0001] The invention relates to nonlinear uncertain system control, in particular to a three-speed intelligent PID control. Background technique [0002] For more than half a century, classical control (cybernetics) based on frequency-domain design methods and modern control (model theory) based on time-domain design methods have developed independently, forming their own methodological systems. In the practice of control engineering, the error between the control target and the actual behavior of the controlled object is easy to obtain and can be dealt with appropriately. Therefore, the prototype of the control strategy of "eliminating error based on error", that is, the PID controller in the actual It has been widely used in the field of industrial control. For practical control engineering problems, since it is usually difficult to give a "description of internal mechanism", the control strategy given by modern control theory based on mathematical models ...

AI Technical Summary

Problems solved by technology

However, the development of science and technology has put forward higher requirements on the accuracy, speed and robustness of the controller, and the shortcomings of PID control have gradually emerged: although PID control can ensure system stability, the dynamic quality of the closed-loop system is sensitive to PID gain changes

This shortcoming leads to an irreconcilable contradiction between "rapidity" and "overshoot" in the control system. Therefore, when the operating conditions of the system change, the gain of the controller needs to change accordingly, and this is also the result of various improved PID The original motivation of control methods such as adaptive PID, nonlinear PID, neuron PID, intelligent PID, fuzzy PID, expert system PID, etc.

Although various improved PIDs can improve the adaptive control capability of the system through online tuning of the controller gain parameters, however, for the control problems of nonlinear uncertain systems, the existing PID control is still powerless, especially the anti-disturbance ability is relatively weak. Difference

In addition, the principle of PID control is to weight and sum the past (I), present (P) and future (change trend D) of the error to form a control signal, although effective control can be applied as long as the three gain parameters of PID are reasonably selected, however , the error and the integral and differential of the error are physical quantities of three different attributes, and the inventor believes that it is unreasonable to form the PID control law model by independently weighting and summing the physical quantities of the three different attributes:

[0003] (1) It not only violates the basic rules of arithmetic operations (physical quantities of different dimensions cannot be weighted and summed independently), but also cannot accurately understand the mathematical model of traditional PID control law in a physical sense;

[0004] (2) The mathematical model of the traditional PID control law separates and treats three links with different attributes, such as proportionality, integral and differential, and treats them independently, which leads to the fact that the three links of proportionality, integral and differential are independent of each other and independent of each other in the control process. As a result, there is a lack of scientific thought of coordinated control;

[0005] (3) Because of the irrationality of the traditional PID control law model, for more than 80 years, the problem of PID parameter tuning has been the main problem that plagues scholars and engineers in the field of control science and control engineering at home and abroad.

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